Topological Isomerism of Möbius-Shaped Aramide Macrocycles Induced by Host-Guest Interactions.

In contrast to traditional Möbius molecules characterized by fully conjugated backbones, synthetic amide-linked Möbius-shaped macrocycles represent a hitherto-unreported class of topological architectures. Here we report the rational design of the first hydrogen-bonded Möbius-shaped aramide macrocycles. Central to this design are intramolecular hydrogen bonds within a para-linked aromatic segment, which critically stabilize the conformation and lock the macrocyclic ring into a single-twist topology. Crystallographic analyses unambiguously confirm their single-twisted Möbius-shaped architectures, while LOL-π calculations support sustained electronic delocalization across the macrocyclic backbones. Notably, a reversible topological switching between a single-twisted Möbius-shaped and a planar Hückel-shaped conformation occurs upon the introduction of water clusters, which occupy the central cavity and competitively disrupt the para-linker hydrogen bonds. Furthermore, complexation with chiral amino acids induces characteristic circular dichroism responses, successfully translating host-guest recognition into distinct chiroptical outputs. This work establishes a fully amide-linked macrocyclic platform that enables stimuli-responsive interconversion between Möbius- and Hückel-shaped conformations.